23 Jul
2006
23 Jul
'06
8:56 a.m.
Hi,
sequence [] = return [] sequence (action:actions) = do x <- action xs <- sequence actions return (x:xs)
sequence_ [] = return () sequence_ (action:actions) = do action sequence_ actions
So, by appending an underscore at the end of a name, you massively improve the runtime behaviour of the program. That to me sounds like a hack :) Would it not be possible to add a GHC rule like the following: forall a b . sequence a >> b = sequence_ a >> b I'm not sure if thats correct, a valid rule definition, or semantics preserving, but if it was it would be nice :) Thanks Neil